We plan to continue along the five main chapters outlined in the progress report: A. The study of the relationships between the tertiary and quaternary structures of E. coli tryptophanase will be pursued, using limited proteolysis in addition of the physico-chemical techniques. The folding of denatured chymotrypsinogen will be further studied. B. The mechanism of allosteric interactions will be studied at the molcular level, using nuclear magnetic resonance and possibly electron spin resonance. C. The sequencing of aspartokinase I- homoserine dehydrogenase I will be pursued, as well as the determinations of the association areas between the two regions of the protein and between protomers. D. The two other maltose permease components as well as the possible interactions between lamb receptor and maltose permease will be investigated. E. The main effort in this section will be the characterization of the cholinergic receptor proteins from Electrophorus electricus and (or) Torpedo marmorata.